Faced with severe crowding in two Prince William County high schools, school officials introduced four optional school boundary changes to the School Board last night. Up to 360 ninth-grade students in the eastern end of the county could be affected next fall, depending on which plan the board adopts next month after public hearings.

Only Osbourn Park, Woodbridge and Gar-Field high schools are included in the plans. But school officials stressed that all the options have been developed with an eye toward the future. Each can be modified when boundaries are redrawn for the fall of 1991, when a new high school will open just west of Dale City.

Three of the four optional plans would make the student body of Woodbridge High School more consistently affluent by removing students from the working-class Marumsco area of Woodbridge and sending them to Gar-Field, officials said.

In turn students in the upper middle-class areas of Old Bridge and West Ridge, who now go to Osbourn Park, would go to Woodbridge.

"Those plans do not present the best socioeconomic balance," acknowledged Associate Superintendent Robert Ferrebee.

A fourth option would keep students from the Marumsco residential areas at Woodbridge and send the Old Bridge and West Ridge students to Gar-Field.

Public meetings on the plans will be held Jan. 21 at Osbourn Park and at 7:30 p.m. Jan. 25 at Gar-Field.